Public health messages are seen during morning rush hour at Canary Wharf underground station, following the outbreak of the coronavirus disease (COVID-19), London, Britain, June 1, 2020. REUTERS/Toby Melville

RTS39UZT

June 01, 2020

Public health messages are seen during morning rush hour at Canary Wharf underground station, following...

Public health messages are seen during morning rush hour at Canary Wharf underground station, following the outbreak of the coronavirus disease (COVID-19), London, Britain, June 1, 2020. REUTERS/Toby Melville

RTS39UZS

June 01, 2020

Public health messages are seen during morning rush hour at Canary Wharf underground station, following...

Public health messages are seen during morning rush hour at Canary Wharf underground station, following the outbreak of the coronavirus disease (COVID-19), London, Britain, June 1, 2020. REUTERS/Toby Melville

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June 01, 2020

Quiet escalators are seen during morning rush hour at Canary Wharf underground station, following the...

Quiet escalators are seen during morning rush hour at Canary Wharf underground station, following the outbreak of the coronavirus disease (COVID-19), London, Britain, June 1, 2020. REUTERS/Toby Melville

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May 27, 2020

A man wearing a protective face mask is seen at Westminster underground station, following the outbreak...

A woman wearing a protective face mask makes her way in an underground passage of Tokyo station during a rush hour which has fewer passengers than before amid the coronavirus disease (COVID-19) outbreak in Tokyo, Japan, May 21, 2020.REUTERS/Kim Kyung-Hoon

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May 21, 2020

Guards try to catch a bird in an underground passage of Tokyo station amid the coronavirus disease (COVID-19)...

A woman wearing a protective face mask makes her way in a underground passage of Tokyo station during a rush hour which has fewer passengers than before amid the coronavirus disease (COVID-19) outbreak in Tokyo, Japan, May 21, 2020.REUTERS/Kim Kyung-Hoon

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May 19, 2020

A general view as people are seen on a platform at North Acton underground station following the outbreak...

A woman is seen wearing a protective face mask on a platform at North Acton underground station following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 19, 2020. REUTERS/John Sibley

RTX7JJ4R

May 19, 2020

A woman is seen wearing a protective face mask on a platform at North Acton underground station following...

A woman is seen wearing a protective face mask on a platform at North Acton underground station following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 19, 2020. REUTERS/John Sibley

RTX7JJ4N

May 19, 2020

A man is seen wearing a protective face mask on a platform at North Acton underground station following...

A man is seen wearing a protective face mask on a platform at North Acton underground station following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 19, 2020. REUTERS/John Sibley

RTX7JJ4F

May 19, 2020

Police officers are seen on a bridge over North Acton underground station following the outbreak of the...

People wearing protective face masks are seen boarding a train at North Acton underground station following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 19, 2020. REUTERS/John Sibley

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May 18, 2020

A lady goes down the escalator at Canary Wharf Underground Station in London, following the outbreak...

A man wearing a face mask is seen on an escalator at Canary Wharf Underground Station in London, following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 18, 2020. REUTERS/Simon Dawson

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May 18, 2020

People are seen on escalators at Canary Wharf Underground Station in London, following the outbreak of...

Workers are seen standing on "Keep Clear" signs on the ground at Waterloo Underground Station in London, following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 18, 2020. REUTERS/Simon Dawson

A woman is seen wearing a protective face mask on an escalator at a London underground station following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 14, 2020. REUTERS/Henry Nicholls

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May 14, 2020

A sign is seen at a London underground station following the outbreak of the coronavirus disease (COVID-19),...

People are seen wearing protective face masks as they wait on a platform at Westminster underground station following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 14, 2020. REUTERS/Henry Nicholls

RTX7IV46

May 14, 2020

People step off a train at Clapham Common underground station following the outbreak of the coronavirus...

A woman is seen wearing a protective face mask on a platform at Clapham Common underground station following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 14, 2020. REUTERS/Henry Nicholls

RTX7IV2U

May 14, 2020

A woman is seen wearing a protective face mask on a platform at London Bridge underground station following...

A woman is seen wearing a protective face mask on a platform at London Bridge underground station following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 14, 2020. REUTERS/Henry Nicholls

RTX7IV2T

May 14, 2020

A man is seen wearing a protective face mask on a platform at Kennington underground station following...

A man is seen wearing a protective face mask on a platform at Kennington underground station following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 14, 2020. REUTERS/Henry Nicholls

RTX7IV2J

May 14, 2020

A man is seen wearing a protective face mask on a London underground train following the outbreak of...

A man is seen wearing a protective face mask on a platform at Clapham Common underground station following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 14, 2020. REUTERS/Henry Nicholls

RTX7IV24

May 14, 2020

People are seen on a platform at Clapham Common underground station following the outbreak of the coronavirus...

A woman is seen wearing a protective face mask as she gets on a train at London Bridge underground station following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 14, 2020. REUTERS/Henry Nicholls

RTX7IUZS

May 14, 2020

People are seen wearing protective face masks on a platform at Clapham Common underground station following...

People are seen wearing protective face masks on a platform at Clapham Common underground station following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 14, 2020. REUTERS/Henry Nicholls

RTX7IUZE

May 14, 2020

A man is seen wearing a protective face mask on a London underground train following the outbreak of...

People are seen wearing protective face masks at London Bridge underground station following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 14, 2020. REUTERS/Henry Nicholls TPX IMAGES OF THE DAY

RTX7IUYR

May 14, 2020

People are seen wearing protective face masks at London Bridge underground station following the outbreak...

A woman is seen wearing a protective face mask on a platform at Stockwell underground station following the outbreak of the coronavirus disease (COVID-19), London, Britain, May 14, 2020. REUTERS/Henry Nicholls

RTX7IS62

May 13, 2020

Protesters wearing protective face masks hold placards as they mark the sixth anniversary of the Soma...

Protesters wearing protective face masks hold placards as they mark the sixth anniversary of the Soma mine disaster, where an underground fire sent deadly carbon monoxide killing 301 workers in May 2014, amid the spread of the coronavirus disease (COVID-19), in Istanbul, Turkey May 13, 2020. The plackar reads "Our sorrow is the seed of our anger". REUTERS/Umit Bektas

RTX7IS56

May 13, 2020

Protesters wearing protective face masks hold placards as they mark the sixth anniversary of the Soma...

Protesters wearing protective face masks hold placards as they mark the sixth anniversary of the Soma mine disaster, where an underground fire sent deadly carbon monoxide killing 301 workers in May 2014, amid the spread of the coronavirus disease (COVID-19), in Istanbul, Turkey May 13, 2020. REUTERS/Umit Bektas TPX IMAGES OF THE DAY

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May 13, 2020

A man wearing a mask is seen on a train at a London underground station, following the outbreak of the...